arch/sh/kernel/traps.c

   1 #include <linux/bug.h>
   2 #include <linux/io.h>
   3 #include <linux/types.h>
   4 #include <linux/kdebug.h>
   5 #include <linux/signal.h>
   6 #include <linux/sched.h>
   7 #include <linux/uaccess.h>
   8 #include <asm/unwinder.h>
   9 #include <asm/system.h>
  10
  11 #ifdef CONFIG_BUG
  12 void handle_BUG(struct pt_regs *regs)
  13 {
  14         const struct bug_entry *bug;
  15         unsigned long bugaddr = regs->pc;
  16         enum bug_trap_type tt;
  17
  18         if (!is_valid_bugaddr(bugaddr))
  19                 goto invalid;
  20
  21         bug = find_bug(bugaddr);
  22
  23         /* Switch unwinders when unwind_stack() is called */
  24         if (bug->flags & BUGFLAG_UNWINDER)
  25                 unwinder_faulted = 1;
  26
  27         tt = report_bug(bugaddr, regs);
  28         if (tt == BUG_TRAP_TYPE_WARN) {
  29                 regs->pc += instruction_size(bugaddr);
  30                 return;
  31         }
  32
  33 invalid:
  34         die("Kernel BUG", regs, TRAPA_BUG_OPCODE & 0xff);
  35 }
  36
  37 int is_valid_bugaddr(unsigned long addr)
  38 {
  39         insn_size_t opcode;
  40
  41         if (addr < PAGE_OFFSET)
  42                 return 0;
  43         if (probe_kernel_address((insn_size_t *)addr, opcode))
  44                 return 0;
  45         if (opcode == TRAPA_BUG_OPCODE)
  46                 return 1;
  47
  48         return 0;
  49 }
  50 #endif
  51
  52 /*
  53  * Generic trap handler.
  54  */
  55 BUILD_TRAP_HANDLER(debug)
  56 {
  57         TRAP_HANDLER_DECL;
  58
  59         /* Rewind */
  60         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
  61
  62         if (notify_die(DIE_TRAP, "debug trap", regs, 0, vec & 0xff,
  63                        SIGTRAP) == NOTIFY_STOP)
  64                 return;
  65
  66         force_sig(SIGTRAP, current);
  67 }
  68
  69 /*
  70  * Special handler for BUG() traps.
  71  */
  72 BUILD_TRAP_HANDLER(bug)
  73 {
  74         TRAP_HANDLER_DECL;
  75
  76         /* Rewind */
  77         regs->pc -= instruction_size(ctrl_inw(regs->pc - 4));
  78
  79         if (notify_die(DIE_TRAP, "bug trap", regs, 0, TRAPA_BUG_OPCODE & 0xff,
  80                        SIGTRAP) == NOTIFY_STOP)
  81                 return;
  82
  83 #ifdef CONFIG_BUG
  84         if (__kernel_text_address(instruction_pointer(regs))) {
  85                 insn_size_t insn = *(insn_size_t *)instruction_pointer(regs);
  86                 if (insn == TRAPA_BUG_OPCODE)
  87                         handle_BUG(regs);
  88                 return;
  89         }
  90 #endif
  91
  92         force_sig(SIGTRAP, current);
  93 }